As @arnold said, don't be too hard on yourself. Most of us have done something similar, or of equal magnitude.
I'm really very careful with my equipment - even after years of use, most of it is either still unmarked or showing only the lightest signs of wear. But I've had accidents, too. The day I took delivery of my brand new DA70 f/2.4 Limited, I was swapping it between cameras so I could calibrate the AF fine adjustment if necessary. After removing it from my K-3, I rested it gently on the rear lens cap, which was sitting on top of the cardboard shipping box the lens arrived in. I turned around to get my K-3II and somehow bumped the shipping box, causing the lens to roll off and and drop about 10" onto the hard marble kitchen island. It hit the marble on the front edge, denting it and cracking the black paint finish. The sound was sickening. When I put the lens back on the camera, it worked but didn't sound right when using AF, nor did it feel right when manually focusing. I had to send that lens to be repaired, and I told myself I'd never be so stupid again... but I'm sure the time will come!